Power transmission fluids incorporate various additives in an effort to improve and control friction properties of the fluid. It has been observed that the friction properties of various additives tend to decrease over time. This can lead to undesirable performance of the transmission device, such as shudder in slipping torque converter clutches, instability of dynamic friction in automatic transmission devices, and belt rattle in continuously variable transmissions. Accordingly, there is a need in the art for an additive which can stabilize and improve the friction properties of a transmission fluid over time to compensate for friction properties of the fluid which are otherwise lost over time to extend the useful life of the fluid.